Biomechanical Study Of Facial Superficial Musculoaponeurotic System (SMAS) And Case Analysis Of Repair After Rhytidectomy

Objective： From design, implementation to repair after operation, facialrhytidectomy is a system process combined surgery, anatomy or other medicalknowledge with clinical practice. In order to obtain more security and betterpostoperative effect, it is necessary to pay attention to every detail of this systemprocess and deepen the understanding of rhytidectomy. This research of rhytidectomyfocused on the following two points:①.Conducted biomechanical test of superficialmusculoaponeurotic system (SMAS)—the important anatomical basis of rhytidectomy,and compared the similarity and difference between the upper and lower parts;②Reviewed some cases of repair after rhytidectomy, analyzed problems in the diagnosisand treatment, and provided clinical references to improve the understanding ofrhytidectomy.Methods：①. Four adult cadaveric heads(eight sides) were selected in this study.Anatomize the lateral face from the skin, and get SMAS superficial to parotid masseterfascia from zygomatic arch, down to the front edge of masseter muscle, anterior to thezygomatic major muscle, posterior to mandibular angle. Maintained integrity of SMASthroughout the process. Prepared SMAS samples and test the biomechanical propertiesby the mechanical testing machine, collected and output data by computer.②. Reviewthe clinical cases of repair after rhytidectomy, including four cases of postoperative scar:the frontal hairline scar, temporal scar with alopecia, preauricular scar, to take therestorative treatment. Analized the operation process, and discussed the problems indiagnosis and treatment of repair after rhytidectomy.Results：①. Under the experimental condition of the same strain level, stress decreases with time in SMAS region I (below the zygomatic arch-pretragal-the lateraledge of the zygomatic major muscle-beneath the lobulus auriculae) was less thanregion II (beneath the lobulus auriculae-the lateral edge of the zygomatic major muscle-along the anterior edge of the masseter muscle, intersecting with the rim of themandible-mandibular angle-beneath the lobulus auriculae), Stability of relaxation inregion I was better than that of region II. Under the conditions of same stress level,strain of region II is higher than region I, ultimate strength of region I is higher than thatin region II. Parameters of two regions were different.②. The clinical cases afterrhytidectomy were successfully repaired by targeted therapeutic interventions. Thetreatment effect was obvious without flap necrosis, hematomas effusion or infection,facial nerve injury and other complications.Conclusion：①.Biomechanical testing of facial SMAS provides a new method forresearch on SMAS, biomechanical performance of two parts (region I, II) is different,and the difference may be associated with clinical observations.②.Scar repair afterrhytidectomy is special, should be based on comprehensive judgment according toclinical data, the inform in advance and preparation are required. Repair afterrhytidectomy, need to be familiar with basic anatomy of face, but also need distinguishability of tissue disturbance after operation. The prosthetics including scar repair arecomponent of the overall process of rhytidectomy, pay attention to every detail in theprocess, can we obtain more satisfactory effects.